Harry Potter for (all) the ages.(Now Playing)

One scourge of contemporary moviegoing is when parents bring young children to wildly inappropriate pictures. If you've been to a theater lately you've probably seen this: babies' screams competing with the howling werewolves of Van Helsing; tykes asking their rooms why Paris is doing that to Helen in Troy.

What a nice contrast it is, then, to attend a Harry Potter film--the third of which, Harry Potter and the Prisoner of Azkaban, came out in early June. At one of these movies the experience is exactly the opposite of running into underage kids at a grown-up film. Here you'll find adults filling seats meant for kids. And enjoying themselves enormously.

The phenomenon goes back to the novels on which the movies are based. J. K. Rowling's kid lit has been devoured by readers of all ages. Still, the filmmakers could have fumbled the multigenerational appeal of these stories. It's tricky to deliver a movie that all ages can enjoy. The simpler route is just to deliver the children's version, full of bright colors and bathroom jokes, and leave grown-ups out.

But that isn't the way great children's movies are made. From Disney's Snow White and the Seven Dwarves to Shrek 2, classic kids' films have woven childlike imagination with the wisdom of experience. They allow adults to feel the elation of youth while giving youngsters a taste of the burdens that come with being an adult.

Even more than in the first two installments of the series, that give-and-take between child and adult themes plays out delightfully in Prisoner of Azkaban, which follows our hero Harry (Daniel Radcliffe) as he negotiates the onset of adolescence. If the first two movies, which traced this young wizard's introduction into a hidden world of magic, were about a child learning to see himself as unique rather than a misfit, then Prisoner of Azkaban ...